The structural characteristics mainly refer to the micropore volume, specific surface area and micropore structure, etc. Ordinary activated carbon has high ash content, small pore volume, wide distribution of micropores, small specific surface area and poor adsorption performance
www.coconutactivatedcarbon.comThe physical properties of activated carbon, such as specific surface area and pore size distribution, have great influence on its adsorption capacity.
china active carbonAt present, there are three methods to modify surface structural characteristics: physical method, chemical method and physical-chemical combination method, the latter two methods are more commonly used.The micro-structure of activated carbon can be achieved by microwave heating, neutron radiation and low temperature plasma technology.
Microwave modification is to control the surface chemical composition or element content of activated carbon by adjusting the microwave power and radiation time, so as to adjust the surface chemical properties of activated carbon and improve the adsorption performance of activated carbon. It is an effective method to change the adsorption performance of activated carbon.Some studies have found that after the activated carbon by microwave irradiation, the surface become rough, is in the shape of concave and convex, many backwater hole was opened and extends into, the pores attachments to be removed, the carbon skeleton to contract, different size of hole shrinkage, jung, entrance to drop, pore size distribution in the direction of microporous migration, thus effectively improve the adsorption ability of active carbon, enhance the adsorption ability of refractory organic matter
When the activated carbon is treated by ultrasonic wave, the ultrasonic cavitation will cause shock wave and microjet, and the different ultrasonic treatment time and physical parameters will have different effects on the properties of activated carbon.
Yu Fengwen et al. 1 found that the pore size of activated carbon was changed by ultrasonic modification, and the BET specific surface area and micropore specific surface area of activated carbon decreased slightly with the extension of ultrasonic treatment time.
In order to make the activated carbon material have more abundant void structure and more uniform pore size distribution, some activators are often added in the activation process.
The commonly used activators are alkali metals, hydroxides of alkali earth metals, inorganic salts and some acids. At present, the more widely used and more mature chemical activators are KOH, NaOH, ZnCH, CaCb and H.PO, etc."Different activators and their dosages make the preparation of activated carbon more flexible, among which the super activated carbon prepared by KOH as the activator has the best performance.
The normal activated carbon treated by alternating modification of acid and alkali not only increased the adsorption capacity of benzene but also increased its specific surface area.Super activated carbon with specific surface area up to 3886 m2/g can be prepared from the ordinary coal char activated carbon modified by potassium hydroxide, which greatly improves the adsorption capacity of activated carbon
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